A device described in Japanese Laid-Open Patent Publication No. 2005-197234 has recently been proposed as an electroluminescence device capable of large-area (e.g., 0.25 m2 or more) light emission with high luminance and long lifetime.
Meanwhile, structures described in Japanese Laid-Open Patent Publication Nos. 2007-026989 and 10-289602 have been known as a vehicle light containing a conductive film capable of preventing illuminance reduction of the light.
The illuminance of a vehicle light may be reduced due to the following causes:    (1) adhesion and accumulation of snow on the outer circumferential surface of the front cover,    (2) adhesion and freezing of rain water or car wash water on the outer circumferential surface of the front cover, and    (3) progression of (1) and (2) due to use of an HID lamp light source having a high light intensity even under low power consumption (a small heat generation amount).
The structure described in Japanese Laid-Open Patent Publication No. 2007-026989 is obtained by attaching a heating element containing a transparent electricity insulating sheet and a conductive pattern printed thereon to a formed lens using an in-mold method. Specifically, the conductive pattern of the heating element is composed of a composition containing a noble metal powder and a solvent-soluble thermoplastic resin.
The structure described in Japanese Laid-Open Patent Publication No. 10-289602 is obtained by attaching a heating element into a lens portion of a vehicle lamp. The lens portion is heated by applying an electric power to the heating element under a predetermined condition. The document describes that the heating element comprises a transparent conductive film of ITO (Indium Tin Oxide), etc.
Furthermore, a device described in Japanese Laid-Open Patent Publication No. 2006-190585 has been proposed as a dye-sensitized solar cell capable of reducing adverse effects of reflected electromagnetic waves without significant reduction of the power generation efficiency. In addition, in the field of electromagnetic-shielding films, Japanese Laid-Open Patent Publication No. 2004-221565 has disclosed a technology for determining a thickening ratio of line intersections in a mesh to minimize PDP image quality deterioration due to moire or the like.